Fluid dosing system

ABSTRACT

A dosing engine including a framework, fluid drivers, and a flow control device. The framework has an inlet that receives a fluid and an outlet that dispenses the fluid. The fluid drivers are supported by the framework and pump fluid toward the outlet. The flow control device is coupled to the framework and is in fluid communication with the inlet, the outlet, and the fluid drivers. The fluid drivers are cooperatively driven by a motive force from fluid flow through the inlet to dispense fluid via the outlet, and to drive the flow control device to distribute diluent to the diluent drivers in a coordinated manner.

CROSS-REFERENCE TO RELATED APPLICATIONS

This patent application is a continuation of U.S. patent applicationSer. No. 17/610,967, filed Nov. 12, 2021, which is the U.S. nationalstage entry under 35 U.S.C. § 371, of International Patent ApplicationNumber PCT/US2020/044090, filed Jul. 29, 2020, which claims priority toU.S. Provisional Application No. 62/879,893, filed Jul. 29, 2019, andU.S. Provisional Application No. 62/978,563, filed Feb. 19, 2020, theentire contents of each of which are hereby incorporated by reference.

BACKGROUND

The present invention relates to a chemical dosing system, and moreparticularly to a rotary dosing system that can dispense differentchemical dilutions.

SUMMARY

Many industries rely on systems that mix one or more chemicals and wateror another suitable fluid. These systems require a means of consistentlyand accurately providing doses of chemicals to the appropriate amount ofwater to create a correctly diluted solution. The goal is for the systemto create effective solutions without wasting chemical.

In one aspect, the invention provides a dosing engine including aframework that has at least three housings and a wall defining a centralchamber in communication with each of the at least three housings viachamber inlets and chamber outlets, and a piston disposed in each of theat least three housings. Each piston and housing cooperate to define apiston-cylinder arrangement, and the pistons are cooperatively drivenbetween respective first positions and second positions by a motiveforce. The dosing engine also includes a valve assembly that ispositioned in the central chamber and that is configured to be in fluidcommunication with a diluent inlet and a diluent outlet. The valveassembly is rotatable via the motive force for intake of diluent and asecond position for dispense of diluent. The dosing engine furtherincludes at least one chemical pump assembly that is attached to theframework and that is driven by the motive force to intake and dispensea chemical concentrate.

In another aspect, the invention provides a dosing engine including aframework that defines a central chamber, and three or more pistons thatare coupled to the framework within respective housings. Each piston andhousing cooperate to define a piston-cylinder arrangement. The dosingengine also includes a valve assembly that is positioned in the centralchamber and that is configured to be in fluid communication with asource of diluent via a diluent inlet and a diluent outlet. The dosingengine further includes at least one chemical pump assembly that isattached to the framework and that is configured to be in fluidcommunication with a source of chemical concentrate. A single motiveforce is configured to drive the three or more pistons betweenrespective first positions and second positions. The single motive forceis further configured to rotate the valve assembly to intake diluent anddispense diluent, and to drive the chemical pump assembly to intake anddispense the chemical concentrate.

In another aspect, the invention provides a dosing engine including adiluent pump that has a framework with an inlet and an outlet anddefining a central chamber, a valve assembly positioned in the centralchamber, and three or more pistons disposed in the framework andcooperating with the framework to define piston-cylinder assemblies thatare reciprocated between a first position and a second position by amotive force. The inlet is configured to be connected to a source ofdiluent. The valve assembly has an intake valve in fluid communicationwith the inlet and a discharge valve that is in fluid communication withthe outlet. The dosing engine also includes a chemical pump that has achemical piston and first and second sleeves. The chemical piston isconfigured to reciprocate within the sleeves via the motive force. Thevalve assembly also is configured to rotate via the motive force.

In another aspect, the invention provides a dosing engine including aframework, fluid drivers, and a flow control device. The framework hasan inlet that receives a fluid and an outlet that dispenses the fluid.The fluid drivers are supported by the framework and pump fluid towardthe outlet. The flow control device is coupled to the framework and isin fluid communication with the inlet, the outlet, and the fluiddrivers. The fluid drivers are cooperatively driven by a motive forcefrom fluid flow through the inlet to dispense fluid via the outlet, andto drive the flow control device to distribute diluent to the diluentdrivers in a coordinated manner.

In another aspect, the invention provides a dosing engine including aframework, fluid drivers, a drive mechanism and a flow control device.For example, the framework has an inlet that receives a fluid and anoutlet that dispenses the fluid. The fluid drivers are supported by and,in some cases, radially arranged on the framework. In cases where thefluid drivers are radially arranged, the fluid drivers are angularlyspaced around the framework and pump fluid toward the outlet. The drivemechanism is coupled to the framework and is operatively coupled to thefluid drivers. The flow control device is at least partially disposed inthe framework and is operatively coupled to the drive mechanism. Forexample, the flow control device is in fluid communication with theinlet, the outlet, and the fluid drivers, and the flow control device isdefined by one or more cams and one or more valves to sequence flow offluid to and from the fluid drivers in response to movement of the drivemechanism.

In another aspect, the invention provides a method of dispensing afluid. The method includes directing a fluid through an inlet of aframework. The framework support fluid drivers that at least partiallydefine pump chambers associated with the fluid drivers. The method alsoincludes cooperatively moving the fluid drivers via a motive force fromfluid flow into the framework to dispense fluid to an outlet, anddriving a flow control device in response to the cooperative movement ofthe fluid drivers to distribute diluent to the fluid drivers in acoordinated manner.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of an exemplary dosing system including adosing engine that has a mechanism 64 pump, chemical pump assemblies,and a drive mechanism.

FIG. 2 is a perspective view of a portion of the dosing engine of FIG. 1exposing features of two of the chemical pump assemblies.

FIG. 3A is an elevation view of the dosing engine of FIG. 1 from a firstside.

FIG. 3B is an elevation view of the dosing engine of FIG. 1 , with aportion of the drive mechanism removed for clarity.

FIG. 4 is an elevation view of the dosing engine of FIG. 1 from a secondside.

FIG. 5 is an elevation view of the dosing engine with portions of thedosing engine removed to illustrate fluid pistons, chemical pistons, andthe axes along which fluid pistons and chemical pistons move.

FIG. 6 is a cross-section view of the mechanism 64 pump taken along line6-6 of FIG. 3A.

FIG. 7 is a cross-section view of the mechanism 64 pump and the drivemechanism taken along line 7-7 of FIG. 3A.

FIG. 8 is an exploded view of the mechanism 64 pump and the drivemechanism of FIG. 1 illustrating a dosing engine framework, a valveassembly, and mechanism 64 pistons.

FIG. 9 is a perspective view of the dosing engine framework of FIG. 8 .

FIG. 10 is a cross-section view of the dosing engine framework of FIG. 9taken along line 10-10 in FIG. 9 .

FIG. 11 is an exploded perspective view of the valve assembly includinga first valve and a second valve, and a portion of the drive mechanism.

FIG. 12A is a perspective view of the first valve of FIG. 11 .

FIG. 12B is an elevation view of the first valve from the left side ofFIG. 12A.

FIG. 12C is a perspective view of the valve assembly illustrating thefirst and second valves.

FIG. 12D is another perspective view of the valve assembly of FIG. 11 .

FIG. 12E is an elevation view of the valve assembly illustrating thefirst and second valves mated together.

FIG. 12F is an elevation view of the valve assembly illustrating thefirst and second valves spaced apart from each other.

FIG. 13 is a perspective view of one mechanism 64 piston of FIG. 8 .

FIG. 14A is an elevation view of a one chemical pump assemblyillustrating inlets and outlets, the chemical piston, and the chemicaldrive assembly.

FIG. 14B is a perspective view of a portion of the chemical pumpassembly with the housing made transparent to illustrate the chemicalpiston, pump chambers, and chemical drive assembly.

FIG. 14C is another perspective view of a portion of the chemical pumpassembly with the housing made transparent to illustrate the chemicalpiston, pump chambers, and chemical drive assembly.

FIG. 14D is a perspective view of two adjacent, parallel chemical pumpassemblies, with a portion of the housing removed for clarity.

FIG. 14E is a perspective view of a portion of two adjacent chemicalpump assemblies illustrating chemical pistons, chemical pump chambers,and chemical drive assemblies.

FIG. 15 is a perspective view of the dosing engine of FIG. 1illustrating the drive mechanism, with portions of the drive mechanismand the chemical pump assembly transparent for the sake of clarity.

FIG. 16 is an exposed view of the rotary dosing system illustrating thedosing engine in a first state with a first diluent piston, a seconddiluent piston, and a third diluent piston in respective strokepositions.

FIG. 17 is an exposed view of the rotary dosing system illustrating thedosing engine in a second state with the mechanism 64 pistons indifferent respective stroke positions relative to FIG. 16 .

FIG. 18 an exposed view of the rotary dosing system illustrating thedosing engine in a third state with the mechanism 64 pistons indifferent respective stroke positions relative to FIGS. 16 and 17 .

FIG. 19 is a schematic of the rotary dosing system illustrating thedosing engine, chemical concentrate sources, a fluid source, and a mixchamber.

FIG. 20 is a perspective view illustrating another exemplary dosingsystem including a dosing engine that has a mechanism 64 pump and adrive mechanism.

FIG. 21 is another perspective view of the dosing engine of FIG. 20illustrating the dosing engine and an inlet and an outlet of themechanism 64 pump.

FIG. 22 is an exploded perspective view of the dosing engine of FIG. 20illustrating various components of the dosing system.

FIG. 23 is an exploded perspective view of one side of the drivemechanism of FIG. 20 , including a mechanical linkage and a valve crankgear.

FIG. 24 is an exploded perspective view of the valve crank gear and aninlet shaft of the pump.

FIG. 25 is a perspective view of the dosing engine of FIG. 21 with thecrank arms and the valve crank gear removed to illustrate portions ofthe mechanism 64 pump, including a seal plate and an inlet shaft.

FIG. 26 is a perspective view of an inner side the seal plate of FIG. 25.

FIG. 27 is a perspective view of one mechanism 64 piston of the dosingengine of FIG. 20 , including a piston head, a piston skirt, and apiston seal.

FIG. 28 is a view of the mechanism 64 pump illustrating valve crankgears, and portions of an inlet valve assembly and an outlet valveassembly, with poppets removed for clarity.

FIG. 29 is a section view of the mechanism 64 pump illustrating theframework, the inlet valve assembly, the outlet valve assembly, and pumpchambers.

FIG. 30 is a perspective view of the inlet valve assembly and the outletvalve assembly.

FIG. 31 is a perspective view of a portion of the inlet valve assembly.

FIG. 32 is a perspective view of a portion of the outlet valve assemblywith an outlet shaft and a pressure seal.

FIG. 33 is a perspective view of a portion of the dosing engine similarto FIG. 32 with the outlet shaft and the pressure seal removed toillustrate an outlet cam.

FIG. 34A is a perspective view of the framework on the outlet side.

FIG. 34B is a perspective view of a portion of the dosing engine similarto FIG. 33 with the outlet cam removed to illustrate poppets of thevalve assembly on the outlet side.

FIG. 35 is a perspective view of a portion of the dosing engine with thecenter shaft removed to illustrate an inlet pressure cam and inlet-sidepoppets.

FIG. 36A is a perspective view of the framework on the inlet side.

FIG. 36B is a perspective view of a portion of the dosing engine of FIG.35 with the inlet pressure cam removed to illustrate the inlet-sidepoppets and the inlet-side lift cam.

FIG. 37A is a view of the inlet valve assembly, including a bore seal, alift cam, poppets (with some removed for clarity), aninlet-side-pressure cam, and an inlet shaft.

FIG. 37B is a perspective view of the lift cam, poppets, theinlet-side-pressure cam, the inlet shaft, and poppets (with some removedfor clarity).

FIG. 37C is a perspective view of the lift cam.

FIG. 37D is a perspective view of the inlet pressure cam.

FIG. 37E is another perspective view of the inlet pressure cam.

FIG. 37F is a perspective view of the inlet shaft.

FIG. 37G is another perspective view of the inlet shaft.

FIG. 37H is a view of the outlet valve assembly, including poppets, anoutlet pressure cam, a seal plate, and an outlet shaft.

FIG. 37J is a perspective view of the outlet pressure cam.

FIG. 37K is another perspective view of the outlet pressure cam.

FIG. 37L is a perspective view of the outlet shaft.

FIG. 37M is another perspective view of the outlet shaft.

FIG. 38A is a section view across the inlet and outlet of the dosingengine illustrating fluid flow through the inlet and the outlet, andinto and out of a mechanism 64 pump chamber relative to the inlet-sidechamber and the outlet-side chamber, respectively.

FIG. 38B is another section view across the inlet and outlet of thedosing engine illustrating fluid flow through the inlet and the outlet,and into and out of a mechanism 64 pump chamber relative to theinlet-side chamber and the outlet-side chamber, respectively, with somepoppets removed for clarity.

FIG. 39 is a section view across the inlet side the dosing engineillustrating fluid flow through the system.

FIG. 40 is a section view across the outlet side of the dosing engineillustrating fluid flow through the system.

FIG. 41 is a section view across the outlet side of the dosing engineillustrating the positions of the pistons relative to the outlet-sidechamber in a state of operation of the dosing engine.

FIG. 42A is a section view illustrating a stroke of one piston andrelative positions of the poppets associated with the piston duringoperation of the dosing engine.

FIG. 42B is a section view illustrating a stroke of one piston andrelative positions of the poppets associated with the piston duringoperation of the dosing engine.

FIG. 42C is a section view illustrating a stroke of one piston andrelative positions of the poppets associated with the piston duringoperation of the dosing engine.

FIG. 42D is a section view illustrating a stroke of one piston andrelative positions of the poppets associated with the piston duringoperation of the dosing engine.

FIG. 42E is a section view illustrating a stroke of one piston andrelative positions of the poppets associated with the piston duringoperation of the dosing engine.

FIG. 42F is a section view illustrating a stroke of one piston andrelative positions of the poppets associated with the piston duringoperation of the dosing engine.

FIG. 42G is a section view illustrating a stroke of one piston andrelative positions of the poppets associated with the piston duringoperation of the dosing engine.

FIG. 42H is a section view illustrating a stroke of one piston andrelative positions of the poppets associated with the piston duringoperation of the dosing engine.

FIG. 43A illustrates piston position relative to the angular position ofpistons in a three-piston dosing engine consistent with what is shown inFIG. 1 .

FIG. 43B illustrates fluid flow rate relative to the angular position ofpistons in a three-piston dosing engine consistent with what is shown inFIG. 1 .

FIG. 43C illustrates piston torque relative to the angular position ofpistons in a three-piston dosing engine consistent with what is shown inFIG. 1 .

FIG. 44A illustrates piston deflection relative to the angular positionof pistons in a five-piston dosing engine consistent with what is shownin FIG. 20 .

FIG. 44B illustrates dosing engine flow rate relative to the angularposition of pistons in a five-piston dosing engine consistent with whatis shown in FIG. 20 .

FIG. 44C illustrates piston torque relative to the angular position ofpistons in a five-piston dosing engine consistent with what is shown inFIG. 20 .

Before any embodiments of the present invention are explained in detail,it should be understood that the invention is not limited in itsapplication to the details or construction and the arrangement ofcomponents as set forth in the following description or as illustratedin the drawings. The invention is capable of other embodiments and ofbeing practiced or of being carried out in various ways. It should beunderstood that the description of specific embodiments is not intendedto limit the disclosure from covering all modifications, equivalents andalternatives falling within the spirit and scope of the disclosure.Also, it is to be understood that the phraseology and terminology usedherein is for the purpose of description and should not be regarded aslimiting.

DETAILED DESCRIPTION

FIGS. 1 and 19 illustrate an exemplary dosing system including a dosingengine or dispenser 10 (e.g., a rotary dosing engine or rotarydispenser) that is coupled to a fluid or diluent source 12 (e.g., awater or other fluid source) and chemical reservoirs 14 (e.g.,containers, bags, tanks, etc.) for mixing fluid and chemical in a mixchamber 16. The dosing engine 10 includes a fluid or diluent pump 17(referred to as a ‘diluent pump’ for purposes of description only),chemical drivers or pump assemblies 18, and a drive mechanism 19 thatoperatively couples the pump 17 and the chemical pump assemblies 18 todispense predetermined amounts of diluent and a selected chemical intothe mix chamber 16. As shown in FIG. 19 , the mix chamber 16 is locateddownstream of the dosing engine 10.

With reference to FIGS. 1-10 , the diluent pump 17 includes a framework34 that has an inlet 38, an outlet 42, a central chamber 44 (best seenin FIGS. 8 and 9 ), and housings 46 (FIGS. 2 and 5 ). The inlet 38 isfluidly coupled to the diluent source 12 (e.g., via piping, conduit, orhoses) and connects the diluent source 12 to the central chamber 44. Theoutlet 42 fluidly connects the central chamber 44 to the mix chamber 16.It will be appreciated that the pump 17 can be used with fluids otherthan a diluent.

With reference to FIGS. 9 and 10 , the central chamber 44 is defined bya wall 50 with an interior surface of revolution about a central axis A(see FIGS. 7, 8, and 10 ). The illustrated central chamber 44 includes afirst or intake chamber section 52 and a second or discharge chambersection 54. Each chamber section 52, 54 is defined by a cylindricalportion 52 a, 54 a, respectively, on the outer or lateral extent of thecentral chamber 44 (left and right sides of the chamber 44 as viewed inFIG. 10 ; along the axis A), and a tapered portion 52 b, 54 b,respectively, that tapers radially inward relative to the central axisA. The tapered portions 52 b, 54 b terminate at a ridge 56. It will beappreciated that the central chamber 44 can have a different profile andstill function in the manner described herein. The inlet 38 fluidlycommunicates with the intake chamber section 52, and the outlet 42fluidly communicates with the discharge chamber section 54.

The housings 46 are attached to the central chamber 44 (e.g., by weldingor formed integral with the central chamber 44 via a molding or formingprocess) and extend outward from the central chamber 44. As best seen inFIG. 5 , the framework 34 has three housings 46, although it will beappreciated that the framework 34 may have fewer or more than threehousings 46 (e.g., two housings, five housings, etc.). The illustratedhousings 46 are cylindrical, but it will be appreciated that thehousings 46 can have other shapes (e.g., oblong, polygonal, elliptical,etc.). As shown in FIGS. 5 and 9 , the housing 46 has an end wall 58that joins with (e.g., partially shares) the wall 50. In someembodiments, the end wall 58 can be completely separate from (and stillattached to) the wall 50. Each housing 46 also has slots 60 that extendfrom a distal end of the housing 46 axially inward along a piston axis Btoward the end wall 58.

As shown in FIGS. 5-8 , the diluent pump 17 also includes fluid drivers62 (e.g., illustrated as pistons) and a flow control device 64 (e.g.,illustrated as a valve assembly or valve mechanism). For purposes of thedescription, the terms ‘valve assembly’ and ‘valve mechanism’ are usedas examples of a flow control device. One piston 62 is disposed in acorresponding housing 46, and each housing-piston combination defines apiston-cylinder arrangement. It will be appreciated that the term‘piston-cylinder’ encompasses more than a cylindrical housing 46, andthat the shape of the housing 46 and the piston head can have shapesother than cylindrical (e.g., oblong, polygonal, elliptical, etc.). Inaddition, each piston 62 defines an exemplary pump mechanism of thedosing engine 10 that is supported by the framework 34 and that pumpsfluid from the inlet 38 to the outlet 42 in a coordinated manner withthe other pump mechanisms. For purposes of the description and theclaims, the terms ‘fluid driver’ or ‘diluent driver’ shall be broadlyconstrued as a pump mechanism that can include the piston 62, or anotherpump mechanism that is designed to pump a fluid. The term ‘flow controldevice’ shall be broadly construed to include the valve mechanism 64 oranother mechanism or assembly that controls flow of fluid through theframework 34.

With reference to FIG. 13 , the diluent piston 62 is defined by a bodythat has a piston head 66 and arms 68 that are connected to the pistonhead 66 by a neck portion 70. The piston head 66 is shaped consistentwith the shape of the housing 46, and has a channel 72 that carries aseal 74. With reference to FIGS. 1-4, 6 , land 13, the arms 68 extendlaterally outward from the body and extend through the slots 60 when thediluent piston 62 is positioned in the housing 46. As shown, the arms 68include a fastener or attachment 76 (e.g., snap-protrusions) on therespective ends of the arms 68 that attach the diluent piston to thedrive mechanism 19. The arms 68 may be coupled to the drive mechanism 19in any suitable manner (e.g., by fasteners, pins, etc.) that facilitatesreciprocation of the diluent piston 62 in the housing 46.

The housing 46, including the end wall 58, and the piston head 66cooperate to define a diluent pump chamber 78 that is in fluidcommunication with the central chamber 44. More specifically, and withreference to FIG. 10 , the diluent pump chamber 78 is in fluidcommunication with the intake chamber section 52 via a first aperture orpump chamber inlet 80. The diluent pump chamber 78 also is in fluidcommunication with the discharge chamber section 54 via a secondaperture or pump chamber outlet 82. The seal 74 fluidly seals thediluent pump chamber 78 to prevent leakage of diluent from the diluentpump chamber 78 beyond the piston head 66.

Each diluent piston 62 reciprocates within the corresponding housing 46between a first or intake position (referred to herein as a “diluentintake position” for purposes of clarity) and a second or dischargeposition (referred to herein as a “diluent discharge position” forpurposes of clarity). The diluent intake position corresponds to thestate of the diluent piston 62 where diluent has been fully drawn intothe diluent pump chamber 78 (e.g., a “bottom dead-center” position orpriming position; see upper left piston-cylinder arrangement in FIG. 16). The diluent discharge position corresponds to the state of thediluent piston 62 where diluent has been fully discharged from thediluent pump chamber 78 (a “top dead-center” position or dischargingposition; see upper right piston-cylinder arrangement in FIG. 16 ).Movement of the diluent piston 62 from the diluent intake position tothe diluent discharge position discharges diluent from the diluent pumpchamber 78, and movement of the diluent piston 62 from the diluentdischarge position to the diluent intake position draws diluent into thediluent pump chamber 78.

As shown in FIGS. 5-8 , the illustrated valve mechanism 64 is disposedin the central chamber 44 and controls the flow of diluent between theinlet 38, the outlet 42, the central chamber 44, and each diluent pumpchamber 78. With reference to FIGS. 6, 7, 11A-12C, the valve mechanism64 is rotatable within the central chamber 44 about the axis A. Thevalve mechanism 64 includes a first or intake valve (e.g., first valveportion) 110 a and a second or discharge valve (e.g., second valveportion) 110 b. As illustrated, the intake valve 110 a and the dischargevalve 110 b are the same, with the discharge valve 110 b positioned inthe central chamber 44 in an orientation that is 180° relative to theorientation of the intake valve 110 a.

Because the intake valve 110 a and the discharge valve 110 b are thesame, it should be understood that generic reference numerals will beused to identify the valve features, including the valves themselves(i.e. the generic reference numeral for each valve is ‘110’). Wherethere is a need to differentiate between the intake valve 110 a and thedischarge valve 110 b, the features of the intake valve 110 a will bereferred to with reference numerals having the character ‘a’, andfeatures of the discharge valve 110 b will be referred to with referencenumerals having the character ‘b’. Also, while the illustratedembodiment includes distinct valves 110 a, 110 b that are coupled toeach other, it should be appreciated that the valve assembly may beintegrally formed as a monolithic element.

FIG. 12A-12F illustrate that the valve 110 has a body 114 with an axisof rotation C (the axis A and C are collinear when the valve 110 ispositioned in the central chamber 44). The body 114 is defined by acircular segment in cross-section (see FIG. 12B), and extends along theaxis of rotation C such that the body 114 has a truncated frusto-conicalprofile. Stated another way, the body 114 has a first side 118 that isdefined by a first planar surface 122, a second side 126 that is definedby a second planar surface 130, and an outer surface 134 that extendsand radially tapers between the first planar surface 122 and the secondplanar surface 130. A shelf 138 is defined on the second side 126 andextends through the axis of rotation C. The body 114 also has a chordsurface 142 that extends between opposite edges of the outer surface134. As shown in FIG. 12B, the outer surface 134 defines a circular arcthat is larger than 180° from one edge of the outer surface 134 to theother edge of the outer surface 134.

With continued reference to FIGS. 12A-12F, a fastener post 146 andalignment posts 150 extend linearly outward from the first side 118, anda flange 154 extends radially outward from the body 114 adjacent thesecond side 126. The fastener post 146 is positioned on the axis ofrotation C, and the alignment posts 150 are diametrically opposite eachother relative to the fastener post 146. The fastener post 146 is ahollow column that receives a fastener 158 (FIG. 11 ). In someembodiments, the fastener post 146 is threaded to receive the fastener158. In other embodiments, springs or other devices can be used tosecure the valves 110 a, 110 b to each other in the central chamber 44.The alignment posts 150 are shown as solid columns, although thealignment posts 150 can be hollow. The flange 154 has a circular segmentprofile when viewed from the side or in cross-section. The radius ofcurvature for the flange 154 is equal to the radius of curvature for thesecond side 126.

When the intake valve 110 a and the discharge valve 110 b are fullypositioned in the central chamber 44 (i.e. the intake valve 110 a ispositioned in the intake chamber section 52 and the discharge valve ispositioned in the discharge chamber section 54), the second side 126 amates with the second side 126 b such that the shelves 138 a, 138 b areengaged with each other. As explained in detail below, engagement of theshelves 138 a, 138 b permit coordinated rotation of the valves 110 a,110 b. The outer surfaces 134 a, 134 b are complementary to and engageor mate with the tapered portions of the intake chamber section 52 andthe discharge chamber section 54, respectively. Also, the radial extentsof the flanges 154 a, 154 b are aligned with and engage opposite sidesof the ridge 56.

With reference to FIGS. 6 and 7 , the wall 50 and the intake valve 110 acooperate to define an intake chamber 160 that selectively fluidlycouples to the inlet 38 and the diluent pump chambers 78 depending onthe rotational position of the valve mechanism 64. The wall 50 and thedischarge valve 110 b cooperate to define a discharge chamber 162 thatselectively fluidly couples to the outlet 42 and the diluent pumpchambers 78 depending on the rotational position of the valve mechanism64. The complementary mating between the valves 110 a, 110 b and thewall 50 seal the respective chambers 160, 162 from each other.

With reference to FIGS. 1-5 , the chemical pump assemblies 18 (sometimesreferred to as chemical drivers) are coupled to the framework 34 betweenthe housings 46 (e.g., snapped onto the framework 34, or attached by anadhesive or other fasteners or fastener combinations, engaged by one ormore hinges, etc.). As shown, the dosing engine 10 has four chemicalpump assemblies 18, although fewer or more than four chemical pumpassemblies 18 may be included on the dosing engine 10.

The chemical pump assemblies 18 are arranged in pairs that are attachedat each of two locations on the framework 34. As illustrated in FIGS.3A-5 , the pairs of chemical pump assemblies 18 share a pump housing 166(e.g., a two-piece shell). It should be appreciated that each chemicalpump assembly may have its own pump housing. Each chemical pump assembly18 includes a chemical pump 174 that, as illustrated, takes the form ofa piston pump. The chemical pump 174 can take other forms, such a lobepump, an internal gear pump, or another type of pump that can deliver achemical concentrate to the mix chamber 16.

With reference to FIGS. 2, 5, and 14A-18 , each chemical pump assembly18 includes a chemical piston 178 that is defined by a first piston head180 on one end and a second piston head 182 on the opposite end, and apiston rod 184 that interconnects the first and second piston heads 180,182. The chemical pump assembly 18 also includes a first sleeve 185 thatdefines a first chemical pump chamber 186 and that houses the firstpiston head 180, and a second sleeve 188 that defines a second chemicalpump chamber 190 and that houses the second piston head 182. The firstchemical pump chamber 186 is fluidly connected to a first chemical inlet192 and a first chemical outlet 194, and the second chemical pumpchamber 190 is fluidly connected to a second chemical inlet 196 and asecond chemical outlet 198. The inlets 192, 196 and the outlets 194, 198extend through the pump housing 166. The dual inlets 192, 196 and thedual outlets 194, 198, along with the piston heads 180, 182 and thecorresponding chambers 186, 190, cooperate to define a reciprocating,dual-action piston pump that dispenses chemical based on motion of thepiston in each direction. Each piston head 180, 182 carries a seal toprevent leakage of chemical concentrate behind the respective pistonheads 180, 182. In some embodiments, one or more of the

The piston rod 184 includes a hole 199 that connects the chemical piston178 to a chemical drive assembly 200 to enable reciprocal movement ofthe chemical piston 178 such that each piston head 180, 182 moves abetween a first or intake position (referred to herein as a “chemicalintake position” for purposes of clarity) and a second or dischargeposition (referred to herein as a “chemical discharge position” forpurposes of clarity). The chemical intake position corresponds to thestate of the piston head 180 or the piston head 182 where chemicalconcentrate has been fully drawn into the chemical pump chamber 186, 190associated with the piston head that is in the chemical intake position(e.g., the piston head 180 is in the chemical intake position in FIG. 15). The chemical discharge position corresponds to the state of thepiston head 180 or the piston head 182 where chemical concentrate hasbeen fully discharged from the chemical pump chamber 186, 190 associatedwith the piston head that is in the chemical discharge position.

Movement of the piston head 180 or the piston head 182 from the chemicalintake position to the chemical discharge position discharges chemicalconcentrate from the associated chemical pump chamber 186, 190, andmovement of the chemical piston head 180 or the chemical piston head 182from the chemical discharge position to the chemical intake positiondraws chemical concentrate into the associated chemical pump chamber186, 190. It will be appreciated that when one piston head is in thechemical intake position, the other piston head is in the chemicaldischarge position, and that each piston head 180, 182 will be incomplementary positions when the chemical piston 178 is reciprocated. Asillustrated, the piston rod 184 has two holes 199, one of which isconnected to the chemical drive assembly 200. In some embodiments, oneor more of the chemical pump assemblies 18 may be selectively engaged ordisengaged relative to the drive mechanism 19 (e.g., by disconnectingpart of the drive assembly 200 between the drive mechanism 19 and thechemical pump assembly 18).

The chemical drive assembly 200 is the same for each chemical pumpassembly 18. With reference to FIGS. 14A-14E, the chemical driveassembly 200 includes a connecting rod 204, a crank gear 208, a chemicaldriven gear 212, and a drive gear mechanism 216. The connecting rod 204has a protrusion 220 to pin the connecting rod 204 to the piston rod184, and a hole 224 on the opposite end of the connecting rod 204 thatreceives a pin 224 and the crank gear 208. The crank gear 208 is meshedwith the driven gear 212 (e.g., via teeth on each of the crank gear 208and the driven gear 212). The driven gear 212 is pinned to a sidewall ofthe pump housing 166, and is meshed (e.g., via teeth) with the drivegear mechanism 216. The drive gear mechanism 216 includes a drive gear228 and a transfer gear 232. The drive gear 228 has a shaft 236 thatextends through the sidewall of the housing 166, and the transfer gear232 is keyed to the shaft 236. As illustrated, the transfer gear 232 hasteeth that mesh with the driven gear 212. It will be appreciated thatthe gears may be operatively connected or meshed with each other in waysother than via teeth. Also, the gears 208, 212, 228, 232 are sizedrelative to each other (i.e. the gears 208, 212, 228, 232 haverespective gear ratios) to drive the chemical piston heads 180, 182between the chemical intake positions and the chemical dischargepositions. Furthermore, as explained in more detail below, the gearratios are selected to work in tandem or cooperation with the drivemechanism 19 so that diluent and chemical concentrate reach the mixchamber 16 at the same time and in the desired proportions.

The chemical drive assemblies 200 are operatively coupled to the drivemechanism 19 so that one or more of the chemical pumps 174 deliver apredetermined amount of chemical concentrate to the mix chamber 16 insequence with delivery of a predetermined amount of diluent from thediluent pump 17. With reference to FIGS. 1, 2, and 6-8 , the drivemechanism 19 has parallel drive assemblies 240 a, 240 b that arepositioned on opposite, lateral sides of the framework 34 and thatcooperate to drive the diluent pump 17 and the chemical pump assemblies18. The drive assemblies 240 a, b are the same, and features of eachdrive assembly 240 a, 240 b will be annotated with the character ‘a’ and‘b’, respectively for ease in understanding the system.

With reference to FIGS. 1-4, 14B, 14C, 15 and 19 , the drive assemblies240 a, 240 b respectively include a valve crank gear 244 a, 244 b, aprimary crank arm 248 a, 248 b, and secondary crank arms 252 a, 252 b.FIGS. 6-8 and 11 show that valve crank gear 244 a has a body thatcarries a seal 256 a, and a central aperture 260 a through which thefastener 158 a extends to secure the valve crank gear 244 a to theintake valve 110 a via the fastener post 146 a. The valve crank gear 244a also has alignment recesses or pockets 264 a diametrically oppositeeach other that align and mate with the alignment posts 150 a to securethe valve crank gear 244 a to the intake valve 110 a in a rotationallyfixed manner. Similarly, the valve crank gear 244 b has a body thatcarries a seal 256 b, and a central aperture 260 b through which thefastener 158 b extends to secure the valve crank gear 244 b to thedischarge valve 110 b via the fastener post 146 b. The valve crank gear244 b also has alignment recesses or pockets 264 b diametricallyopposite each other that align and mate with the alignment posts 150 bto secure the valve crank gear 244 b to the discharge valve 110 b in arotationally fixed manner. It should be understood that ‘rotationallyfixed’ means that the dependent or complementary rotation of the intakevalve 110 a and the discharge valve 110 b transfers to the valve crankgears 244 a, 244 b that are attached to the lateral or outer extents ofthe valve mechanism 64. In other words, the valve crank gears 244 a, 244b rotate with the valve mechanism 64.

Each valve crank gear 244 a, 244 b also includes a pin 268 a, 268 b thatextends outward from the valve crank gear 244 a, 244 b opposite the sideof the valve crank gear 244 a, 244 b that is connected to the valvemechanism 64. The pin 268 a, 268 b is located on adjacent the perimeterof the valve crank gear 244 a, 244 b (i.e. at a radial extent of thecrank valve gear 244 a, 244 b). The primary crank arm 248 a, 248 b has acentral hole 272 a, 272 b that attaches to the pin 268 a, 268 b so thatrotation of the valve crank gear 244 a, 244 b transfers to movement ofthe primary crank arm 248 a, 248 b about the axis A. As illustrated, theprimary crank arm 248 a, 248 b is snapped onto the pin 268 a, 268 b,although other connections are considered herein.

FIGS. 1, 2, 3A, 4 , each primary crank arm 248 a, 248 b includes aplurality of crank pins 276 a, 276 b that are positioned adjacent aperimeter of the primary crank arm 248 a, 248 b (i.e. positioned at aradial extent on the crank arm 248 a, 248 b). As illustrated, eachprimary crank arm 248 a, 248 b has two crank pins 276 a, 276 b that arespaced apart from each other at a 120° angle having a center on thecentral hole 272 a, 272 b. In some embodiments, each primary crank arm248 a, 248 b may have fewer or more than two crank pins 276 a, 276 b(generally corresponding to the quantity of secondary crank arms 252 a,252 b included in the drive mechanism 19).

Each of the primary crank arms 248 a, 248 b and the secondary crank arms252 a, 252 b are defined by elongated rods with distal ends that havepiston arm holes 280 a, 280 b. The piston arm holes 280 a, 280 b connectthe crank arms 248 a, 248 b, 252 a, 252 b to the respective arms 68 onthe diluent pistons 62 (e.g., the crank arms 248 a, 248 b, 252 a, 252 bsnap onto the arms 68). As illustrated, the primary crank arms 248 a,248 b connect to the same diluent piston 62 on the opposite arms 68 ofthat piston 62. In addition, the secondary crank arm pairs (i.e. thesecondary crank arms 252 a, 252 b that are parallel to each other)connect to the same diluent pistons 62 in the same manner.

The pinned connection of the primary crank arms 248 a, 248 b to thevalve crank gear 244 a, 244 b, and the pinned connections of thesecondary crank arms 252 a, 252 b to the primary crank arm 248 a, 248 bdefine slider crank mechanisms or similar mechanical linkages thattransfer linear or reciprocal movement of the diluent pistons 62 withinthe housings 46 to rotation of the valve mechanism 64. The connectionsof the secondary crank arms 252 a, 252 b to the primary crank arms 248a, 248 b define a diluent pump 17 with pump chambers 78 that are phasedor out-of-sync with each other. For example, the Figures show that thedosing engine 10 has three diluent pump chambers 78 and three parallelcrank arm pairs. This means that the diluent pistons 62 are ⅓^(rd)out-of-phase or out-of-sync such that, when one piston 62 is in thediluent intake position, another piston 62 will be in the diluentdischarge position, and the third piston 62 will be in a positionbetween the diluent intake position and the diluent discharge position.It will be appreciated that the dosing engine 10 may include more thanthree diluent pistons 62 in respective housings 46, and the sequencingor out-of-phase relationship of the diluent pistons 62 will be driven bythe quantity of diluent pistons 62. Also, while the drive mechanism 19and the chemical drive assembly 200 are described separately, it will beapparent from the exemplary dosing system described relative to FIGS.1-19 that the drive mechanism 19 inherently drives the chemical pumps174. As such, the chemical drive assembly 200 can be subsumed in or partof the drive mechanism 19 in some embodiments.

To assemble the dosing engine 10, the intake valve 110 a is insertedinto the intake chamber section 52 and discharge valve 110 b is insertedinto the discharge intake section 54 so that the second sides 126 a, 126b, as well as the shelves 138 a, 138 b, are oriented to engage and matewith each other. Next, the valve crank gear 244 a (with the seal 256 a)is positioned on the intake side of the valve mechanism 64 and isattached to the intake valve 110 a by aligning the alignment pockets 264a with the alignment posts 150 a and securing the valve crank gear 244 ato the intake valve 110 a via the fastener 158 a. The valve crank gear244 b (with the seal 256 b) is positioned on the discharge side of thevalve mechanism 64 and is attached to the discharge valve 110 b byaligning the alignment pockets 264 b with the alignment posts 150 b andsecuring the valve crank gear 244 b to the discharge valve 110 b via thefastener 158 b. The pistons 62 are positioned in the framework 34 sothat the arms 68 are disposed in the slots 60. The primary crank arms248 a, 248 b are attached to (e.g., snapped onto) the respective valvecrank gears 244 a, 244 b and onto the arms 68 of one of the pistons 62.The secondary crank arms 252 a, 252 b are then attached to (e.g.,snapped onto) the primary crank arms 248 a, 248 b and to the arms 68 ofthe remaining pistons 62.

Each chemical pump assembly 18 is assembled by inserting the chemicalpiston 178 into the housing 166 so that the piston heads 180, 182 aredisposed in the respective sleeves 185, 188. The connecting rod 204 isattached to the piston rod 184, and then to the crank gear 208 that isattached to the sidewall of the housing 166. The driven gear 212 isattached to the post on the sidewall of the housing 166 and is meshedwith the crank gear 208. The shaft 236 of the drive gear 228 is insertedthrough the housing 166, and the transfer gear 232 is keyed to the shaft236 and meshed with the driven gear 212. Each chemical pump assembly 18is attached to the framework 34 so that the drive gear 228 meshes withthe corresponding valve crank gear 244 a, 244 b.

In general, the order of assembly for the components of the dosingengine 10 can vary, with the main exception being that the valvemechanism 64 must be installed in the central chamber 44 before thedrive mechanism 19 is assembled.

In operation, and with reference to the Figures (and particularly FIGS.16-18 ), the dosing engine 10 self-primes the pistons 62 when waterflows through the inlet 38 and the intake valve 110 a, and into at leastone of the pump chambers 78. Stated another way, diluent entering thesystem defines the motive force for the dosing engine 10 and drivesmovement of the pistons 62, which in turn rotates the valve mechanism 64and drives the chemical pump assemblies 18. A pressure differential thatis generated between the inlet 38 and the outlet 42 cause the pistons 62to reciprocate within the housings 46, which in turn rotate the valvemechanism 64. When a piston 62 moves toward the diluent intake position(see FIG. 16 , upper left piston 62), the piston head 66 draws diluentinto the diluent pump chamber 78. When the piston 62 is in the diluentintake position, the volume of the diluent pump chamber 78 defines theamount of diluent to be dispensed to the mix chamber 16 via subsequentmovement of the piston toward (and to) the diluent discharge position.Movement toward the diluent discharge position dispenses (i.e. pushes)diluent through the pump chamber outlet 82, into the discharge chamber162, and through the outlet 42 for mixing with chemical concentrate inthe mix chamber 16.

Incorporation of three or more pistons 62 in the dosing engine 10 meansthat the valve mechanism 64 is never at a ‘dead’ or inoperable state.The valve mechanism 64 rotates within the central chamber 44 toselectively permit and selectively prevent fluid communication betweenthe diluent pump chambers 78 and the intake chamber 160 and thedischarge chamber 162. The intake valve 110 a and the discharge valve110 b are 180° out-of-phase such that only the pump chamber inlet 80 orthe pump chamber outlet 82, and not both, is in fluid communication withthe intake chamber 160 or the discharge chamber 162. Stated another way,the valve bodies 114 a, 114 b sequentially blocks or unblocks flow ofdiluent through the inlet 80 and the outlet 82.

More specifically, when the piston 62 moves toward the diluent intakeposition, the intake valve 110 a is in a rotational position in whichthe body 114 a permits flow of diluent from the intake chamber 160through the pump chamber inlet 80 into the diluent pump chamber 78associated with the piston 62 because the outer surface 134 a is notengaged with the section of the wall 50 in the area of the pump chamberinlet 80. At the same time, the discharge valve is in a rotationalposition in which the body 114 b blocks flow of fluid from the diluentpump chamber 78 through the pump chamber outlet 82 via engagement of theouter surface 134 b with the wall 50 in the area of the outlet 82. Whenthe piston 62 moves toward the diluent discharge position, the intakevalve 110 a is in a rotational position in which the body 114 a blocksflow of fluid from the intake chamber 160 through the pump chamberoutlet 82 associated with the piston 62 because the outer surface 134 ais engaged with the wall 50 in the area of the pump chamber outlet 82.At the same time, the discharge valve 110 b is in a rotational positionin which the body 114 b does not block the pump chamber outlet 82, sodiluent flows into the discharge chamber 162 as the piston 62 movestoward the diluent discharge position.

The drive mechanism 19 sequences the linear or reciprocal movement ofthe diluent pistons 62 so that diluent is constantly being taken into atleast one pump chamber 78 and being dispensed from another pump chamber78. The drive assemblies 240 a, 240 b move with the valve mechanism 64to drive the pistons 62 to and between the intake and dischargepositions as described above. FIG. 43A illustrates the relativepositions of a three-piston system consistent with what is describedrelative to FIGS. 1-19 , and shows that at no point is the system in a‘dead’-state where fluid is not entering or leaving the system. FIG. 43Billustrates the flow associated with the angular positions of thepistons. FIG. 43C illustrates the torque associated with each pistonrelative to the position of the piston.

The drive assemblies 240 a, 240 b also sequentially drive the chemicalpumps 174 via the operative connection to the chemical drive assemblies200 to draw in a desired or predetermined amount of chemical concentratefrom the chemical reservoir(s) 14 and to dispense the chemicalconcentrate through the chemical outlets 196, 198 to the mix chamber 16.Rotation of the valve crank gears 244 a, 244 b drives gear mechanism 216a, 216 b, which in turn transfers rotation to the crank gear 208.Rotation of the crank gear 208 transfers to the connecting rod 204,which reciprocates the chemical pistons 178.

Due to plural inlets 192, 194 and plural outlets 196, 198, and thecorresponding pump chambers 186, 190 on opposite sides of each chemicalpump 174, chemical concentrate can be dispensed on each half stroke ofthe chemical piston 178. It will be appreciated that check valves orother suitable components are in communication with the inlets 192, 194and the outlets 196, 198 to prevent back-flow of chemical concentrate.Because the connecting rods 204 for each chemical pump pair is attachedto opposite piston heads 180, 182 (i.e. the connecting rod for one ofthe chemical pumps 174 in the pair is connected to the piston head 180and the connecting rod for the other chemical pump 174 in the pair isconnected to the piston head 182), reciprocation of the chemical pistons178 is out of phase with one another. Accordingly, when the first piston178 is in the chemical intake position, the second piston 178 is in thechemical discharge position, and vice versa. Accordingly, chemicalconcentrate is constantly being moved into and out of the chemical pumpassemblies 18. This increases the capacity of the system because as oneof the pump chambers 186, 190 loads with chemical concentrate, the otherof the pump chambers 190, 186 unloads or dispenses chemical concentrate.

Each chemical pump 174 is connected to a source of chemical concentrate(e.g., the chemical reservoirs 14). In some embodiments, two or more ofthe chemical pumps 174 can be fluidly coupled to the same chemicalconcentrate (e.g., to dispense larger quantities of chemical concentrateto the mix chamber 16). Likewise, each chemical pump 174 can be fluidlycoupled to different chemical concentrates (e.g., to increase the numberof chemical selections available for mixing). In the context of a dosingengine 10 that has chemical pumps 174 connected to different sources ofchemical concentrate, the chemical pump assembly (or assemblies) 18associated with the desired or selected chemical concentrate areoperatively engaged by the drive mechanism 19 and the associatedchemical drive assembly 200. The remaining chemical pump assembly(ies)18 are disengaged from the drive mechanism 19 and/or the chemical driveassembly 200 so that a different chemical concentrate is not alsodispensed to the mix chamber 16 at the same time as the desired chemicalconcentrate. In circumstances where it is desired for multiple chemicalconcentrates to be mixed with diluent in the mix chamber 16, thechemical pump assemblies 18 associated with the different chemicalconcentrates can be engaged at the same time.

Accordingly, during operation of the dosing engine 10, diluent andchemical concentrate can be constantly pumped to the mix chamber 16 involumetric proportions that correspond to the desired concentration ofthe dilution formed in the mix chamber 16. The system is closed, sothere is no or minimized exposure to air. This means there are very fewscaling problems. In addition, the dosing engine 10 works well at lowpressure (e.g., less than 7 psi) so that the desired dilution ratio ofdiluent and chemical concentrate can be achieved—in a proportionalmanner—under any load condition. Concerns about ‘dirty’ lines in thesystem are eliminated due to the separate dispensing outlets for diluentand chemical concentrate. The dosing engine 10 is water-driven, so powerproduced by the engine 10 may be drawn off to power the engine 10itself, and/or other features (e.g., ‘smart’ or Internet-enabledfeatures). Although the system has been described and illustrated withthree housings 46 and corresponding pistons 62, it will be appreciatedthat additional housings 46 and pistons 62 (e.g., five housings 46 andpistons 62, ten housings 46 and pistons 62, etc.) may make actuation ofthe dosing engine 10 smoother.

In the illustrated embodiment, there are two chemical pump assemblies 18that are coupled to and in fluid communication with chemical reservoirs14 containing different chemicals. In the illustrated embodiment, onlyone of the chemical pump assemblies 18 is active at a time, but inadditional or alternative embodiments, two or more chemical pumpassemblies 18 may be active at the same time.

As a result of the interaction among the fluid pump 17, the chemicalpump assemblies 18, and the drive mechanism 19, the rotary dosing engine10 allows diluent fluid and chemical to be simultaneously andcontinuously pumped from the respective sources to the mix chamber 16.Measurement of the diluent fluid and the chemical flow rates can beeasily determined by monitoring the turns of the valve assembly as well,either mechanically (e.g., with a tachometer or odometer/counter) orelectrically (e.g., with a hall probe).

FIGS. 20-44C illustrate another exemplary dosing system that includes adosing engine 300 (e.g., a rotary dosing engine or rotary dispenser)that can be coupled to a diluent source. As illustrated, the dosingengine 300 has a five-cylinder arrangement. It will be appreciated thatsome or all of the features of the dosing engine 10 can be included inor combinable with the dosing engine 300 (e.g., chemical pumpassemblies, chemical drive assemblies, etc.).

With reference to FIGS. 20-22 , the dosing engine 300 includes a diluentpump 304 and a drive mechanism 305. FIGS. 20-22, 33, 34A, and 36A showthat the diluent pump 304 has a framework 306 with an inlet 312, anoutlet 316, an inlet-side chamber 320, an outlet-side chamber 324, andhousings 328. The inlet 312 is fluidly coupled to a diluent source(e.g., via piping, conduit, or hoses) and connects the diluent source(e.g., diluent source 12) to the inlet-side chamber 320. The outlet 316fluidly connects the outlet-side chamber 324 to a mix chamber (e.g., themix chamber 16). As best shown in FIGS. 34A and 36A, the framework 306has a central opening 322 defined by a wall 336, and each of theinlet-side chamber 320 and the outlet-side chamber 324 has flow channels340 a, 340 b and alignment projections 344 a, 344 b. The flow channels340 a are arranged in the inlet-side chamber 320 equidistant from thecenter of the framework 306 and equidistant from each other, and theflow channels 340 a provide fluid communication between the inlet-sidechamber 320 and corresponding housings 328. The flow channels 340 b arearranged equidistant from the center of the framework 306 in theoutlet-side chamber 324 and equidistant from each other, and the flowchannels 340 b provide fluid communication between the housings 328 andthe outlet-side chamber 324. The alignment projections 344 b aredisposed between the flow channels 340 b. The framework 306 alsoincludes housing mounts 348 that are positioned between at least some ofthe housings 328 so that one or more chemical pump assemblies (e.g.,chemical pump assemblies 18) can be connected to the framework 306. Inaddition or alternatively, the housing mounts 348 may be used to mountthe framework 306 on other structure.

The illustrated framework 306 has five housings 328 that are angularlyspaced equidistant from each other around the inlet-side chamber 320 andthe outlet-side chamber 324 that are located at a central portion of theframework 306. As shown in FIG. 41 , the housings 328 support fluiddrivers 352 (e.g., illustrated as pistons). The illustrated housings 328are cylindrical, but it will be appreciated that the housings 328 canhave other shapes (e.g., oblong, polygonal, elliptical, etc.). As shownin FIGS. 3A, 38B, 39, and 40 , each housing 328 has an opening 356 thatis in communication with either the inlet-side chamber 320 or theoutlet-side chamber 324 based on the state of the dosing engine 300(i.e. based on the position of the piston 352 in the housing 328 and thedirection of travel for the piston 352). One diluent piston 352 isdisposed in a corresponding housing 328, and each housing-pistoncombination defines a piston-cylinder arrangement. It will beappreciated that the term ‘piston-cylinder’ encompasses more than acylindrical housing 328, and that the shape of the housing 328 and thepiston head can have shapes other than cylindrical (e.g., oblong,polygonal, elliptical, etc.). In addition, each piston 352 defines anexemplary pump mechanism of the dosing engine 300 that is supported bythe framework 306 and that pumps fluid from the inlet 312 toward theoutlet 316 in a coordinated manner with the other pump mechanisms. Forpurposes of the description and the claims, the terms ‘fluid driver’ or‘diluent driver’ shall be construed broadly as a pump mechanism that caninclude the piston 352, or another mechanism that is designed to pump afluid.

As best shown in FIG. 21 , each housing 328 also has slots 358 thatextend from a distal end of the housing 328 axially inward along apiston axis (i.e. the slots 358 extend radially on the framework 306).With reference to FIG. 27 , each piston 352 has a body 363 that definesarms 365, a piston head 367 that is supported on an end of the body 363opposite the arms 365 (e.g., coupled to the end of the body 363 ordefined on the end of the body 363), and a seal 369 that is coupled tothe piston head 367. The piston head 367 is generally shaped consistentwith the shape of the housing 328 and has an annular channel thatcarries the seal 369. The illustrated seal 369 is a lip seal that isgenerally used where there is unidirectional pressure, as is the casewith fluid acting on, or being acted on by, the pistons 352. It will beappreciated that other types of seals (e.g., an are possible andconsidered herein. The seal 369 also may be a low friction seal. Whenthe piston 352 is coupled to the framework 306, the space or areabetween the piston head 367 and the housing 328 define a pump chamber372 where fluid can enter and leave via the opening 356.

With reference to FIGS. 20-21, and 27 , the arms 365 extend laterallyoutward from the body 363 and extend through the slots 358 when thepiston 352 is positioned in the housing 328 to connect to the drivemechanism 305 (e.g., via fasteners 375). It will be appreciated that thearms 365 may be operatively coupled to the drive mechanism 305 in otherways. Furthermore, it will be appreciated that the pistons 352 can bereplaced by similar structure (e.g., bellows, etc.).

With reference to FIGS. 21-23 the drive mechanism 305 includes parallelinlet and outlet subassemblies 305 a, 305 b that are positioned onopposite, lateral sides of the framework 306 and that cooperate to drivethe diluent pump 304 (and, in some embodiments, any chemical pumpassemblies, such as an assembly 18, that are coupled to the drivemechanism 305). Each assembly 305 a, 305 b has a valve crank gear 380(labeled 380 a, 380 b in some Figures to distinguish the parallelcomponents) and a crank arm assembly or drive assembly 440 a, 440 b.Each valve crank gear 380 is positioned on the centerline of theframework 306 and includes gear teeth that can engage other features ofa dosing engine 300 (e.g., a chemical drive assembly operably connectedto a chemical pump assembly). The valve crank gear 380 also includes abearing or gear pin 388 that protrudes outward from the outer side ofthe valve crank gear 380 and that is offset from the center of the valvecrank gear 380. FIG. 24 illustrates an interior-facing side of the valvecrank gear 380, which includes a pump assembly attachment feature thatis defined by a central protrusion 392, a shaft key 394, and pockets396.

As shown in FIGS. 23-24 , each drive assembly 384 a, 384 b has a primarycrank arm 400, and secondary crank arms 404. The primary crank arm 400has a base or first end 432 that is rotatably connected to the gear pin388 (e.g., via a fastener 375), and a second end 412 that is connectedto one of the arms 365. The secondary crank arms 404 are rotatablyattached to the first end 432 of the primary crank arm 472 via bearings416 on the primary crank arm 400, and fasteners (e.g., snap fasteners375). The secondary crank arms 404 extend toward and connect torespective arms 365 of the remaining pistons 352. The pinned connectionsof the secondary crank arms 404 to the primary crank arm 400 defineslider crank mechanisms or similar mechanical linkages that transferlinear or reciprocal movement of the pistons 352 within the housings 328to rotational movement of the diluent pump 304.

With reference to FIGS. 22, 29, and 30 , the diluent pump 304 has aninlet flow control device 420 (e.g., illustrated as a valve assembly ora valve mechanism 420) that is positioned on the inlet side of theframework 306, and an outlet flow control device 424 (e.g., illustratedas a valve assembly or a valve mechanism 424) that is positioned on theoutlet side of the framework 306. For purposes of the description, theterms ‘valve assembly’ and ‘valve mechanism’ are used herein as examplesof a flow control device. The inlet valve assembly 420 and the outletvalve assembly 424 are interconnected such that the two assemblies 420,424 rotate together during operation. As shown in FIGS. 29-31, 35, 36B,and 37A-37G, the inlet valve assembly 420 includes a bore seal 428, alift cam 432, inlet valve poppets 436, an inlet pressure cam 440, aninlet shaft 444, and a seal plate 452. As shown in FIGS. 29, 30, 32-34,and 37H-37M, the outlet valve assembly 424 includes outlet valve poppets456, an outlet pressure cam 460, an outlet shaft 464, and a seal plate468.

With reference to FIGS. 28, 29, and 37A, the bore seal 428 is disposedin a center bore 472 in the inlet-side chamber 320 and is annular inshape to receive the inlet shaft 444. The bore seal 428 is coupled tothe inlet shaft 444 to seal the inlet valve assembly 420 relative to theframework 306. FIGS. 29, 31, 36, and 37A-37C show that the lift cam 432is disposed in the inlet-side chamber 320 on the exterior side of thebore seal 428 and is annular so that the inlet shaft 444 can extendthrough the lift cam 432. On the exterior side, the lift cam 432 has abase section 476 and a lift cam ledge 480 that is connected to the basesection 476 by a first cam slope 484 and a second cam slope 488. Thelift cam ledge 480 and the first and second cam slopes 484, 488 extendpartially around the lift cam 432 and are engageable with an undersideof the valve poppets 436 to bias or move the valve poppets 436 to theopen position during rotation of the pump 304. Referring to FIGS. 37Band 37C, the lift cam 432 has a slot or notch 492 that is engageable bythe inlet pressure cam 440 to maintain cooperative fixed rotation asexplained in detail below.

As best shown in FIGS. 36A and 37A-37B, each valve poppet 436 includes astem 496 and a poppet head 500. The stem 496 extends into the flowchannels 340 a in the framework 306, and the poppet head 500 is disposedin the inlet-side chamber 320. A poppet seal 502 (e.g., an O-ring) ispositioned underneath the poppet head 500 to seal the flow channel 340 afrom the inlet-side chamber 320 when the valve poppet 436 is in theclosed position. The valve poppets 436 can be formed from material thatis wear resistant or durable (e.g., durable nylon), or other suitablematerial.

With reference to FIGS. 36B, 37A, 37B, each valve poppet 436 alsoincludes lateral projections 504 and a center projection 508 that extendradially from the poppet head 500. The lateral projections 504 engagethe alignment projections 344 a that extend from the framework 306 intothe inlet-side chamber 320 to limit or prevent rotation of the valvepoppet 436 during movement of the valve poppet 436 between the closedand open positions. The center projection 508 is engageable by the liftcam 432 to lift the valve poppets 436 to the open position. In someconstructions, the valve poppets 436 can be additionally biased to theopen position by springs 512 (see FIG. 37B) that engage a distal end ofthe valve poppets 436 that is disposed in the flow channels 340 a.

FIGS. 28, 29, 31, 35, and 37A, 37B, 37D, 37E show that the inletpressure cam 440 is disposed in the inlet-side chamber 320 on theexterior side of the lift cam 432 and is annular so that the inlet shaft444 can extend through the inlet pressure cam 440. The inlet pressurecam 440 has a base section 516 and a pressure cam ledge 520 that isconnected to the base section 516 by a first cam slope 524 and a secondcam slope 528. The inlet pressure cam 440 also has a key 532 thatextends outward from adjacent the inner wall of the inlet pressure cam440. The key 532 is engageable with the notch 492 to maintain fixedrotation between the lift cam 432 and the inlet pressure cam 440. Thepressure cam ledge 520 and the first and second cam slopes 524, 528extend partially around the inlet pressure cam 440 and are engageablewith the upper side of the poppet heads 500 to bias or move the valvepoppets 436 to the closed position during rotation of the pump 304. Thebase section 476, the lift cam ledge 480, the first cam slope 484, andthe second cam slope 488 cooperate with the base section 516, thepressure cam ledge 520 the first cam slope 524, and the second cam slope528 to define a path for the poppet heads 500 during rotation of thediluent pump 304. Referring to FIGS. 33 and 37E, the inlet pressure cam440 has a slot or notch 536 that is engageable by the inlet shaft 444 tomaintain cooperative fixed rotation between the shaft 444 and the inletpressure cam 440.

As best seen in FIGS. 28, 29, 31, 37A, 37B, and 37F-37G, the inlet shaft444 includes an elongated body with an inner end 540 and an outer end544, and a cam plate 548 that is disposed between the ends 540, 544. Theinner end 540 is shaped to mate with the outlet shaft 464 so that bothshafts 464 rotate in unison. As illustrated in FIG. 37F, the inner end540 has two spaced fingers 552 and a tab 556, and the cam plate 548 hasa key 560 on the side facing the inner end 540. The key 560 engages thenotch 536 in the inlet pressure cam 440 to fix rotation between theinlet shaft 444 and the inlet pressure cam 440. It will be appreciatedthat the inner end 540 can have other features that facilitate interlockwith the outlet shaft 464.

With reference to FIGS. 24, 29, 31, 37A, 37B, and 37G, the outer end 544has shaft extensions 564 that are spaced annularly around the peripheryof the inlet shaft 444 and that engage the pockets 396. The shaft key394 extending from the valve crank gear 380 a is engaged with a slot 568in the outer end 544 between the shaft extensions 564. The illustratedouter end 544 has three extensions 564, but it will be appreciated thatthe outer end 544 can have one, two, or more than three extensions 564to fix rotation between the valve crank gear 380 a and the inlet shaft444. The inlet shaft 444 also has an aperture 572 that receives afastener 576 to secure the valve crank gear 380 a to the inlet shaft444.

With reference to FIGS. 29 and 31 , a bearing or wear plate 580 issupported on the outer side of the inlet pressure cam 440. The wearplate 580 surrounds the cam plate 548 and a portion of the outer end544. A shaft seal 584 is coupled to the outer end 544 to seal theinterior parts of the inlet valve assembly 420. A seal 588 (e.g., anO-ring) is coupled to a seal shelf 592 that is defined on the outerperiphery of the wear plate 580.

FIG. 29 shows that the seal plate 452 is sandwiched between the valvecrank gear 380 a and the inlet shaft 444. The seal plate 452 includes aninner annular neck 596 that is engageable with the cam plate 548, and anouter annular neck 600 that supports a seal 604 and that engages aninner wall 526 of the inlet-side chamber 320. As best shown in FIG. 25 ,the seal plate 452 is secured to the framework 306 by fasteners 608 suchthat the seal plate 452 does not rotate with the valve crank gear 380 aor the inlet valve assembly 420.

With reference to FIGS. 29, 34B, and 37H, the illustrated outlet-sidevalve poppets 456 are the same as the inlet-side valve poppets 436 andeach valve poppet 456 includes the stem 496 and the poppet head 500. Insome constructions, the outlet-side valve poppets 456 may not have thecenter projection 508 because a lift cam is not needed to move theoutlet valve poppets 456 to the open position. Instead, fluid flowtoward the outlet 316 may be sufficient to move the valve poppets 456 tothe open position. A poppet seal 502 (e.g., an O-ring) is positionedunderneath each poppet head 500 to seal the flow channel 340 b from theoutlet-side chamber 324 when the valve poppet 456 is in the closedposition. The valve poppets 456 can be formed from material that is wearresistant or durable (e.g., durable nylon), or other suitable material.

FIGS. 29 and 33 show that the outlet pressure cam 460 is disposed in theoutlet-side chamber 324 and is annular so that the outlet shaft 464 canextend through the outlet pressure cam 460. As shown in FIGS. 28, 37J,and 37K, the outlet pressure cam 460 has a base section 612 and apressure cam ledge 616 that is connected to the base section 612 by afirst cam slope 620 and a second cam slope 624. The illustrated inletpressure cam 460 also has a key 628 that extends outward from adjacentthe inner wall of the outlet pressure cam 460. The key 628 rotates aboutan exterior of the wall 336 defining the opening 322 for the shafts 444,464. The pressure cam ledge 616 and the first and second cam slopes 620,624 extend partially around the outlet pressure cam 460 and areengageable with the upper side of the poppet heads 500 to bias or movethe valve poppets 456 to the closed position during rotation of the pump304. In the closed position, the valve poppets 456 rest or are coupledto an inner wall 630 of the outlet-side chamber 324. The inner wall 630cooperates with the base section 612, the pressure cam ledge 616 thefirst cam slope 620, and the second cam slope 624 to define a path forthe poppet heads 500 on the outlet side during rotation of the diluentpump 304. Referring to FIG. 37K, the outlet pressure cam 460 has a slotor notch 632 that is engageable by the outlet shaft 464 to maintaincooperative fixed rotation between the shaft 464 and the outlet pressurecam 460.

As best seen in FIGS. 28, 29, 37H, 37L, and 37M, the outlet shaft 464includes an elongated body with an inner end 636 and an outer end 640,and a cam plate 644 that is disposed between the ends 636, 640.Consistent with what is explained above with regard to the inlet shaft444, the inner end 636 is shaped to mate with the outlet shaft 464 sothat both shafts 444, 464 rotate in unison. As illustrated in FIG. 37L,37M, the inner end 636 has two spaced fingers 648 and a tab 652, and thecam plate 644 has a key 656 on the side facing the inner end 636. Thefingers 648 are engaged with the inlet shaft 444 in the space betweenthe fingers 552, and the fingers 552 are engaged with the outlet shaft464 in the space between the fingers 648. It will be appreciated thatthe inner end 636 can have other features that facilitate interlock withthe inlet shaft 444. The key 656 engages the notch 632 in the outletpressure cam 460 to fix rotation between the outlet shaft 464 and theoutlet pressure cam 460.

With reference to FIGS. 37L and 37M, the outer end 640 has shaftextensions 660 that are spaced annularly around the periphery of theoutlet shaft 464 and that are engageable with the pockets 396 in thevalve crank gear 380 b. The shaft key 394 extending from the valve crankgear 380 b is engaged with a slot 664 in the outer end 640 between theshaft extensions 660. The illustrated outer end 640 has three extensions660, but it will be appreciated that the outer end 640 can have one,two, or more than three extensions 660 to fix rotation between the valvecrank gear 380 b and the outlet shaft 464. The outlet shaft 464 also hasan aperture 668 that receives a fastener 576 to secure the valve crankgear 380 b to the outlet shaft 464. The valve crank gear 380 b is thesame as the valve crank gear 380 a. As such, the outer end 640 and thevalve crank gear 380 b are engageable with and secured relative to eachother in the same way that the outer end 544 of the inlet shaft 444 andthe valve crank gear 380 a are engaged with and secured relative to eachother.

With reference to FIG. 29 , a bearing or wear plate 672 is supported onthe outer side of the outlet pressure cam 460. The wear plate 672 is thesame as the wear plate 580 and surrounds the cam plate 644 and a portionof the outer end 640. A shaft seal or ring 676 is coupled to the outerend 640 to seal the interior parts of the outlet valve assembly 424. Aseal 680 (e.g., an O-ring) is coupled to a seal shelf 684 that isdefined on the outer periphery of the wear plate 672.

FIG. 29 shows that the seal plate 468 is sandwiched between the valvecrank gear 380 and the outlet shaft 464. The seal plate 468 is the sameas the seal plate 452 and includes an inner annular neck 688 that isengageable with the cam plate 644, and an outer annular neck 692 thatsupports a seal 696 and that engages an inner wall 698 of theoutlet-side chamber 324. The seal plate 468 is secured to the framework306 by fasteners 696 such that the seal plate 468 does not rotate withthe valve crank gear 380 b or the outlet valve assembly 424.

To assemble the dosing engine 300, the inlet valve assembly 420 and theoutlet valve assembly 424 are installed on the framework 306 from theirrespective sides. On the inlet side, the bore seal 428 is inserted intothe center bore 472, and the lift cam 432 is installed over the boreseal 428. Thereafter, the valve poppets 436 (and the correspondingpoppet seals 412) are inserted into respective flow channels 340 a sothat the valve poppets 436 rest on the base section 476, the lift camledge 480, the first cam slope 484, or the second cam slope 488(depending on the orientation of the lift cam 432 relative to the valvepoppets 436). The inlet pressure cam 440 is positioned over the lift cam432 so that the key 532 is engaged with the notch 492 to fix rotationbetween the lift cam 432 and the inlet pressure cam 440. The inlet shaft444 is coupled to the inlet pressure cam 440 via engagement between thekey 560 and the notch 536 so that the inlet pressure cam 440 rotateswith the inlet shaft 444. The wear plate 580 and the shaft seal 584 arecoupled to the outer side of the inlet shaft 444 adjacent the outer end544. The seal plate 452 is then positioned over and the inlet shaft 444,the wear plate 580, and the shaft seal 584 and attached to the framework306. The valve crank gear 380 a is then positioned over the inlet shaft444 so that the pockets 396 align with the shaft extensions 644 and sothat the shaft key 394 is aligned with the slot 568. The remainder ofthe drive mechanism 305 on the inlet side is then attached to the valvecrank gear 380 a.

On the outlet side, the valve poppets 456 (and the corresponding poppetseals 412) are inserted into respective flow channels 340 b so that thevalve poppets 456 rest on the inner wall 698 of the outlet-side chamber324. The outlet pressure cam 460 is positioned over the valve poppets456, and the outlet shaft 464 is coupled to the outlet pressure cam 460via engagement between the key 656 and the notch 632 so that the outletpressure cam 460 rotates with the outlet shaft 464. The outlet shaft 464also is keyed to the inlet shaft 444 due to the complementary featureson the respective inner ends 540, 636. This complementary engagementbetween the shafts 444, 464 defines a flow control device that controlsfluid flow on the inlet and outlet sides of the dosing engine 300.

The wear plate 672 and the shaft seal 676 are coupled to the outer sideof the outlet shaft 464 adjacent the outer end 640. The seal plate 468is then positioned over and the outlet shaft 464, the wear plate 672,and the shaft seal 676, and attached to the framework 306. The valvecrank gear 380 b is then positioned over the outlet shaft 464 so thatthe pockets 396 align with the shaft extensions 660 and so that theshaft key 394 is aligned with the slot 664. The remainder of the drivemechanism 305 on the outlet side is then attached to the valve crankgear 380 b. The pistons 352 are positioned in the framework 306 so thatthe arms 365 are disposed in the slots 358. The primary crank arms 400a, 400 b are attached to (e.g., snapped onto) the respective valve crankgears 380 a, 380 b and onto the arms 365 of one of the pistons 352 sothat the arms 400 a, 400 b rotate relative to the respectiveconnections. The secondary crank arms 404 are then attached to (e.g.,snapped onto) the primary crank arms 400 a, 400 b and to the arms 365 ofthe remaining pistons 352 for relative rotation.

The lift cam 432, the inlet pressure cam 440, and the valve poppets 436,define a valve of the inlet valve assembly 420, and the poppets 456 andthe outlet pressure cam 460 define a valve of the outlet valve assembly424, both of which are driven by the inlet shaft 444 and the outletshaft 464. The valves direct fluid into and out of the pump chambers 372in a coordinated manner based on the state of the valve poppets 436,456. The flow channels 340 a and the openings 356 provide fluidcommunication between the inlet-side chamber 320 and the pump chambers372 based on the state of the poppets 436 (e.g., open or closed, or insome position between open and closed). Likewise, the flow channels 340b and the openings 356 provide fluid communication between the pumpchambers 372 and the outlet-side chamber 320 based on the state of thepoppets 456 (e.g., open or closed, or in some position between open andclosed). Each piston 352 and corresponding pump chamber 372 has twovalve poppets—one inlet valve poppet 436 and one outlet valve poppet456. When one of the two valve poppets 436, 456 is open or moving towardthe open position, the other valve poppet 456, 436 is closed. When thepiston 352 is at a bottom-dead position (closest to the opening 356) ora top-dead position (farthest from the opening 356), both valve poppets436, 456 are generally closed. Depending on the tolerances of thesystem, the poppets 436, 456 may temporarily both be in the closedposition at the same time while transitioning between the inlet andoutlet strokes, although this should be limited to prevent a conditionknown as cylinder knock. Due to the cooperative arrangement between thelift cam ledge 480 and the pressure cam ledge 520 on the inlet side, andthe relative orientation of the pressure cam ledge 616 on the outletside, the valve poppets 436, 456 are varied between the closed and openpositions in a coordinated manner that aligns with the state of thepiston 352 to which the valve poppets 436, 456 correspond.

The bore seal 320 seals the inlet-side chamber 320 from the outlet-sidechamber 324 so that fluid does not flow directly from the inlet-sidechamber 320 to the outlet-side chamber 324. The shaft seals 584, 676,and the seals 588, 680 act as a fluid barrier between the inlet andoutlet shafts 444, 464 and the exterior of the engine 300 such thatfluid within the framework 306 does not escape or otherwise leak.

Depending on the direction of rotation of the diluent pump 304, one ofthe cam slopes 484, 488 lifts at least one of the poppets 436 to theopen position, the lift cam ledge 480 holds the lifted poppet(s) in theopen position, and the other of the cam slopes 488, 484 allows thelifted poppet(s) 436 to move toward the closed position. The basesection 476 of the lift cam 380 allows the valve poppet(s) 436 to be inthe closed position. The base section 516, the pressure cam ledge 520,and the first and second cam slopes 524, 528 on the inlet pressure cam440 complement the action of the valve poppets 436 that is facilitatedby the lift cam 324. That is, the base section 516 permits the valvepoppet(s) 436 to stay open when lifted by the lift cam 432, the pressurecam ledge 520 forces valve poppets 436 to stay closed by engagement withthe respective poppet heads 500 (i.e. when the poppets 436 are alignedwith the base section 476), and the cam slopes 524, 528 permit movementof the valve poppets 436 between their open and closed positions. On theoutlet side, there is no need for a lift cam because the pressure offluid flowing from one or more of the pump chambers 372 is sufficient toforce the corresponding poppet 456 to the open position. The outletpressure cam 460 coordinates movement of the poppet 456 from the openposition back toward, and to, the closed position, and holds the poppet456 in the closed position via the pressure cam ledge 616.

The dosing engine 300 self-primes the pistons 352 when water flowsthrough the inlet 312 and into at least one of the pump chambers 372.Stated another way, diluent entering the system defines the motive forcefor the dosing engine 300 and drives movement of the pistons 352, whichin turn rotates the valve assemblies 420, 424. A pressure differentialthat is generated between the inlet 312 and the outlet 316 causes thepistons 352 to reciprocate within the housings 328, which in turn rotatethe valve assemblies 420, 424. Fluid flows from the inlet 312 throughthe flow channels 340 a associated with the valve poppet(s) 436 that arepartially or fully open. The fluid then enters the corresponding pumpchamber 372 via the opening 356 in the housing 328. The pressure of thefluid forces the corresponding piston 352 to move away from the opening356 toward a top-dead position, which allows more fluid to accumulate inthe pump chamber 372. This action primes the drive mechanism 305, whichbegins movement of the remaining pistons 352 within the respectivehousings 328.

FIGS. 38A-40 generally show a fluid flow path of fluid through thedosing engine 300 and actuation of the pistons 352 within the framework306. FIG. 38A differs from FIG. 38B in that the poppets 436 are removedin FIG. 38B to better show the fluid flow path. The dashed lines inFIGS. 38A-40 indicate the flow paths as described herein.

Each piston 352 is actuatable between an extended position (i.e. thetop-dead position) and a bottom-dead position. The top-dead positioncorresponds to a maximum radius that the piston 352 extends from theaxis of rotation of the diluent pump 304 (through the central opening332), and the bottom-dead position corresponds to the minimum radiusthat the piston 352 can be located from the axis of rotation. Referringto FIG. 41 , Piston 352 a is in the top-dead position, while piston 352b and piston 352 c are both in, or approximately in, the bottom-deadposition. Piston 352 d and piston 352 e are between the top-deadposition and the bottom-dead position and are moving toward or away fromone of these positions. As such, there is no state of the dosing engine300 in which fluid is neither flowing into a pump chamber 372, norflowing from a pump chamber 372. The rotational movement of the valvecrank gears 380, caused by fluid flow in the system, can be used todrive other systems, for example the chemical pump assemblies 18.

The volume of the pump chamber 372, which corresponds to the amount offluid that can be driven out of the system, is defined by the amount oftravel between the bottom-dead position and the top-dead position andthe cross-sectional area of the pump chamber taken across the axis alongwhich the pistons 352 move.

FIGS. 42A-42H illustrate the up-stroke of one piston 352 within itshousing 328 (FIGS. 42B-42D) from the bottom-dead position (FIG. 42A) tothe top-dead position (FIG. 42E), and the down-stroke of the piston 352from the top-dead position back to the bottom dead position (FIGS. 42 f-42H). The corresponding positions of the inlet valve poppet 436 (shownmoving to the open position or in the open position in FIGS. 42B-42D,and closing or in the closed position in FIGS. 42E-42H) and the outletvalve poppet 456 (shown closed in FIGS. 42A-42E and 42H, and movingtoward the open position or in the open position in FIGS. 42F-4G) arealso shown. For example, FIG. 42D illustrates the piston 352 nearing thetop-dead position, and the inlet valve poppet 436 is open but movingtoward the closed position, and the outlet valve poppet 456 is closed.FIG. 43E illustrates that the valve poppets 436, 456 are closed. FIG.42G illustrates that the inlet valve poppet 436 remains closed as thepiston moves to the bottom-dead position, and the outlet valve poppet456 remains open.

FIG. 44A illustrates the relative positions of a five-piston systemconsistent with what is described relative to FIGS. 20-43H, and showsthat at no point is the system in a ‘dead’-state where fluid is notentering or leaving the system. FIG. 44B illustrates the flow associatedwith the angular positions of the pistons. FIG. 44D illustrates thetorque associated with each piston relative to the position of thepiston.

Various exemplary dimensions of the five-cylinder dosing engine 300 arenow provided for context, although other dimensions, especially scaleddimensions, are contemplated. The diluent pump 304 preferably operatesat about 120-180 revolutions per minute (“rpm”). Each cylinder size isabout 28 cubic centimeters. The diluent pump 304 as illustrated has a6-inch diameter but could have other diameters such as a diameter of 4inches. The diluent pump 304 can operate at a fluid pressure of about25-30 pounds per square inch (“psi”), but is intended to operate with aconsistent fluid pressure that is lower, such as 5-15 psi. Also, thediluent pump 304 can operate under large, temporary surges of fluidpressure, for example 100 psi. When such a surge occurs, the diluentpump 304 operates to work down the driving fluid pressure back into anoperation range via pumping the driving fluid. The dosing engine 300pump about 50,000 liters of driving fluid, for example water, over abouta two-year lifespan.

Comparing the three-cylinder dosing engine 10 with the five-cylinderdosing engine 300, FIGS. 43A and 44A illustrate the radial position ofthe pistons relative to the angular position of the rotating componentsof the respective dosing engines. FIGS. 43B and 44B show the sameangular position of the pistons of each dosing engine with a cumulativeflow rate through each engine as a result of the piston movements.Notably, when comparing the cumulative flow of the three-cylinder engine10 with the five-cylinder engine 300, the five-cylinder engine 300provides a relatively smoother cumulative flow. That is, the deltabetween minimum and maximum flow rates of the five-cylinder dosingengine 300 is less than that between the minimum and maximum flow ratesfor the three-cylinder dosing engine when operating at a steady state.This feature of the five-cylinder dosing engine design is advantageousfor maintaining a consistent, steady output and preventing or minimizinga “water hammer” phenomenon in the pistons.

FIGS. 43C and 44C illustrate the toque of each piston of the three- andfive-cylinder dosing engine configurations. The five-cylinder dosingengine 300 has relatively less torque acting on each of the pistons 352than what acts on the pistons of the three-cylinder dosing engine 10,and additionally has a lower change in torque relative to the angularposition of the pistons. These features provide less stress on the pumpparts, and in turn, higher reliability of the dosing engine.

It follows that aspects from both the three-cylinder and thefive-cylinder dosing engines are combinable to meet dosing enginerequirements. For example, the poppets 436, 456, the pressure cams 440,428, and lift cam 380 could be used in a three-piston dosing engine.Similarly, the valve mechanism 64 that is rotatable within the centralchamber 44 of the three-piston engine is adaptable to work with afive-cylinder dosing engine 300. Each dosing engine is adaptable tooperate the chemical pumps 18.

Other aspects not shown herein are combinable with the three-cylinderdosing engine and the five-cylinder dosing engine 300 as disclosedherein. For example, filtration may be fitted on the inlet side of theframework to filter sediment from the dosing engine driving fluid. Whilecorrosion may not be an issue if the dosing engine is generally madefrom plastic or a composite material, sediment, sand, and otherparticulate in the driving fluid could get trapped in the dosing engineand inhibit the actuation of the pump components. A pressure or flowregulator on the inlet of the framework could also be provided toprotect the dosing engine from damagingly high pressure or flow of thedriving fluid into the dosing engine.

1-20. (canceled)
 21. A dosing system comprising: a framework includingan inlet configured to receive a fluid and an outlet configured todispense the fluid; at least three fluid drivers supported by theframework, each of the at least three fluid drivers cooperating with theframework to define respective pump chambers; a drive mechanism coupledto the at least three fluid drivers and configured to sequentially movethe at least three fluid drivers to pump fluid toward the outlet; and aflow control device in fluid communication with the inlet, the outlet,and the at least three fluid drivers to control flow of fluid relativeto the inlet, the outlet, and each of the pump chambers.
 22. The dosingsystem of claim 21, wherein each of the at least three fluid drivers aremovable in a first manner and the flow control device is movable in asecond manner different from the first manner.
 23. The dosing system ofclaim 22, wherein each of the at least three fluid drivers arereciprocally movable and the flow control device is rotatable.
 24. Thedosing system of claim 21, wherein the flow control device includes aninlet valve mechanism and an outlet valve mechanism interconnected withthe inlet valve mechanism to coordinate flow of fluid between the inletand the outlet.
 25. The dosing system of claim 24, wherein the inletvalve mechanism is positioned to distribute fluid to each of the atleast three fluid drivers in a coordinated manner.
 26. The dosing systemof claim 24, wherein the inlet valve mechanism and the outlet valvemechanism rotate together.
 27. The dosing engine of claim 21, whereinthe flow control device is disposed between the at least three fluiddrivers.
 28. The dosing system of claim 21, wherein the drive mechanismis operatively coupled to the flow control device, and wherein a motiveforce from fluid flow through the inlet acts on the fluid drivers and istransferred to the flow control device by the drive mechanism.
 29. Adosing system comprising: a framework including an inlet configured toreceive a fluid and an outlet configured to dispense the fluid; fluiddrivers supported by the framework, each of the fluid driverscooperating with the framework to define respective pump chambers; and adrive mechanism coupled to the fluid drivers and configured to move thefluid drivers out-of-phase with each other to pump fluid toward theoutlet such that the fluid drivers are in different states of pumping,the out-of-phase movement of the fluid drivers continuously drivingfluid from the inlet and continuously driving fluid to the outlet. 30.The dosing system of claim 29, wherein the fluid drivers include threefluid drivers and the three fluid drivers are ⅓^(rd) out-of-phase witheach other such that when a first fluid driver of the three fluiddrivers is in a diluent intake position, a second fluid driver of thethree fluid drivers is in a diluent discharge position, and a thirdfluid driver of the three fluid drivers is in a position between thediluent intake position and the diluent discharge position.
 31. Thedosing system of claim 29, wherein the fluid drivers are defined byrespective piston-cylinder arrangements, and wherein the drive mechanismis defined by a linkage mechanism configured to transfer linear movementof the piston-cylinder arrangements to rotation of the flow controldevice.
 32. The dosing system of claim 29, further comprising one ormore chemical drivers coupled to the framework, wherein the one or morechemical drivers are configured to pump chemical in response to movementof the drive mechanism.
 33. The dosing system of claim 29, furthercomprising a flow control device in fluid communication with the inlet,the outlet, and the fluid drivers to control flow of fluid relative tothe inlet, the outlet, and each of the pump chambers.
 34. The dosingsystem of claim 33, wherein each of the fluid drivers are movable in afirst manner and the flow control device is movable in a second mannerdifferent from the first manner.
 35. The dosing system of claim 34,wherein each of the at least three fluid drivers are reciprocallymovable and the flow control device is rotatable.
 36. The dosing systemof claim 29, wherein the drive mechanism includes a linkage mechanismoperably coupled to each of the fluid drivers, wherein the fluid driversare reciprocally movable by the linkage mechanism, and wherein theout-of-phase movement is configured to continuously drive fluid from theinlet and continuously driving fluid to the outlet without all of thefluid drivers in a dead-center state.
 37. A dosing system comprising: aframework including an inlet configured to receive a fluid and an outletconfigured to dispense the fluid; fluid drivers supported by theframework, each of the fluid drivers having a discharge position and anintake position and cooperating with the framework to define respectivepump chambers; a drive mechanism coupled to the fluid drivers andincluding a linkage mechanism operatively connecting the fluid driversto each other for cooperative movement of the fluid drivers between thedischarge positions and the intake positions; and a flow control devicecoupled to the framework and configured to control flow of fluid betweenthe inlet and the outlet.
 38. The dosing system of claim 37, wherein theflow control device is positioned to control flow of fluid into and outof the fluid drivers.
 39. The dosing system of claim 37, wherein thelinkage mechanism is operatively coupled to the flow control device totransfer reciprocal movement of the fluid drivers to rotational movementof the flow control device.
 40. The dosing system of claim 37, whereinthe linkage system is configured to drive the fluid drivers out-of-phasewith each other to pump fluid toward the outlet such that the fluiddrivers are in different states of pumping.